I mean you have not access to svnadmin, neither you have access to its files system. I'm going to backup source of my project in codeplex.com.
Many Thanks
UPDATE:
I used:
svnsync initialize file:///d:/fardis_repo https://fardis.svn.codeplex.com/svn
but got error:
svnsync: Repository has not been enabled to accept revision propchanges;
ask the administrator to create a pre-revprop-change hook